# -*- coding: utf-8 -*-

"""
***************************************************************************
    TilesXYZ.py
    ---------------------
    Date                 : April 2019
    Copyright            : (C) 2019 by Lutra Consulting Limited
    Email                : marcel.dancak@lutraconsulting.co.uk
***************************************************************************
*                                                                         *
*   This program is free software; you can redistribute it and/or modify  *
*   it under the terms of the GNU General Public License as published by  *
*   the Free Software Foundation; either version 2 of the License, or     *
*   (at your option) any later version.                                   *
*                                                                         *
***************************************************************************
"""

__author__ = 'Marcel Dancak'
__date__ = 'April 2019'
__copyright__ = '(C) 2019 by Lutra Consulting Limited'

import os
import math
from uuid import uuid4

import gdal
import sqlite3
from qgis.PyQt.QtCore import QSize, Qt, QByteArray, QBuffer
from qgis.PyQt.QtGui import QColor, QImage, QPainter
from qgis.core import (QgsProcessingException,
                       QgsProcessingParameterEnum,
                       QgsProcessingParameterNumber,
                       QgsProcessingParameterBoolean,
                       QgsProcessingParameterString,
                       QgsProcessingParameterExtent,
                       QgsProcessingOutputFile,
                       QgsProcessingParameterFileDestination,
                       QgsProcessingParameterFolderDestination,
                       QgsGeometry,
                       QgsRectangle,
                       QgsMapSettings,
                       QgsCoordinateTransform,
                       QgsCoordinateReferenceSystem,
                       QgsMapRendererCustomPainterJob)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm


# TMS functions taken from https://alastaira.wordpress.com/2011/07/06/converting-tms-tile-coordinates-to-googlebingosm-tile-coordinates/ #spellok
def tms(ytile, zoom):
    n = 2.0 ** zoom
    ytile = n - ytile - 1
    return int(ytile)


# Math functions taken from https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames #spellok
def deg2num(lat_deg, lon_deg, zoom):
    lat_rad = math.radians(lat_deg)
    n = 2.0 ** zoom
    xtile = int((lon_deg + 180.0) / 360.0 * n)
    ytile = int((1.0 - math.log(math.tan(lat_rad) + (1 / math.cos(lat_rad))) / math.pi) / 2.0 * n)
    return (xtile, ytile)


# Math functions taken from https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames #spellok
def num2deg(xtile, ytile, zoom):
    n = 2.0 ** zoom
    lon_deg = xtile / n * 360.0 - 180.0
    lat_rad = math.atan(math.sinh(math.pi * (1 - 2 * ytile / n)))
    lat_deg = math.degrees(lat_rad)
    return (lat_deg, lon_deg)


class Tile:
    def __init__(self, x, y, z):
        self.x = x
        self.y = y
        self.z = z

    def extent(self):
        lat1, lon1 = num2deg(self.x, self.y, self.z)
        lat2, lon2 = num2deg(self.x + 1, self.y + 1, self.z)
        return [lon1, lat2, lon2, lat1]


class MetaTile:
    def __init__(self):
        # list of tuple(row index, column index, Tile)
        self.tiles = []

    def add_tile(self, row, column, tile):
        self.tiles.append((row, column, tile))

    def rows(self):
        return max([r for r, _, _ in self.tiles]) + 1

    def columns(self):
        return max([c for _, c, _ in self.tiles]) + 1

    def extent(self):
        _, _, first = self.tiles[0]
        _, _, last = self.tiles[-1]
        lat1, lon1 = num2deg(first.x, first.y, first.z)
        lat2, lon2 = num2deg(last.x + 1, last.y + 1, first.z)
        return [lon1, lat2, lon2, lat1]


def get_metatiles(extent, zoom, size=4):
    west_edge, south_edge, east_edge, north_edge = extent
    left_tile, top_tile = deg2num(north_edge, west_edge, zoom)
    right_tile, bottom_tile = deg2num(south_edge, east_edge, zoom)

    metatiles = {}
    for i, x in enumerate(range(left_tile, right_tile + 1)):
        for j, y in enumerate(range(top_tile, bottom_tile + 1)):
            meta_key = '{}:{}'.format(int(i / size), int(j / size))
            if meta_key not in metatiles:
                metatiles[meta_key] = MetaTile()
            metatile = metatiles[meta_key]
            metatile.add_tile(i % size, j % size, Tile(x, y, zoom))

    return list(metatiles.values())


class TilesXYZAlgorithmBase(QgisAlgorithm):
    EXTENT = 'EXTENT'
    ZOOM_MIN = 'ZOOM_MIN'
    ZOOM_MAX = 'ZOOM_MAX'
    DPI = 'DPI'
    TILE_FORMAT = 'TILE_FORMAT'

    def initAlgorithm(self, config=None):
        self.addParameter(QgsProcessingParameterExtent(self.EXTENT, self.tr('Extent')))
        self.addParameter(QgsProcessingParameterNumber(self.ZOOM_MIN,
                                                       self.tr('Minimum zoom'),
                                                       minValue=0,
                                                       maxValue=25,
                                                       defaultValue=12))
        self.addParameter(QgsProcessingParameterNumber(self.ZOOM_MAX,
                                                       self.tr('Maximum zoom'),
                                                       minValue=0,
                                                       maxValue=25,
                                                       defaultValue=12))
        self.addParameter(QgsProcessingParameterNumber(self.DPI,
                                                       self.tr('DPI'),
                                                       minValue=48,
                                                       maxValue=600,
                                                       defaultValue=96))
        self.formats = ['PNG', 'JPG']
        self.addParameter(QgsProcessingParameterEnum(self.TILE_FORMAT,
                                                     self.tr('Tile format'),
                                                     self.formats,
                                                     defaultValue=0))

    def prepareAlgorithm(self, parameters, context, feedback):
        project = context.project()
        visible_layers = [item.layer() for item in project.layerTreeRoot().findLayers() if item.isVisible()]
        self.layers = [l for l in project.layerTreeRoot().layerOrder() if l in visible_layers]
        return True

    def generate(self, writer, parameters, context, feedback):
        feedback.setProgress(1)

        extent = self.parameterAsExtent(parameters, self.EXTENT, context)
        self.min_zoom = self.parameterAsInt(parameters, self.ZOOM_MIN, context)
        self.max_zoom = self.parameterAsInt(parameters, self.ZOOM_MAX, context)
        dpi = self.parameterAsInt(parameters, self.DPI, context)
        self.tile_format = self.formats[self.parameterAsEnum(parameters, self.TILE_FORMAT, context)]
        tile_width = 256
        tile_height = 256

        wgs_crs = QgsCoordinateReferenceSystem('EPSG:4326')
        dest_crs = QgsCoordinateReferenceSystem('EPSG:3857')

        project = context.project()
        src_to_wgs = QgsCoordinateTransform(project.crs(), wgs_crs, context.transformContext())
        wgs_to_dest = QgsCoordinateTransform(wgs_crs, dest_crs, context.transformContext())

        settings = QgsMapSettings()
        settings.setOutputImageFormat(QImage.Format_ARGB32_Premultiplied)
        settings.setDestinationCrs(dest_crs)
        settings.setLayers(self.layers)
        settings.setOutputDpi(dpi)
        if self.tile_format == 'PNG':
            settings.setBackgroundColor(QColor(Qt.transparent))

        self.wgs_extent = src_to_wgs.transformBoundingBox(extent)
        self.wgs_extent = [self.wgs_extent.xMinimum(), self.wgs_extent.yMinimum(), self.wgs_extent.xMaximum(),
                           self.wgs_extent.yMaximum()]

        metatiles_by_zoom = {}
        metatiles_count = 0
        for zoom in range(self.min_zoom, self.max_zoom + 1):
            metatiles = get_metatiles(self.wgs_extent, zoom, 4)
            metatiles_by_zoom[zoom] = metatiles
            metatiles_count += len(metatiles)

        lab_buffer_px = 100
        progress = 0

        tile_params = {
            'format': self.tile_format,
            'quality': 75,
            'width': tile_width,
            'height': tile_height,
            'min_zoom': self.min_zoom,
            'max_zoom': self.max_zoom,
            'extent': self.wgs_extent,
        }
        writer.set_parameters(tile_params)

        for zoom in range(self.min_zoom, self.max_zoom + 1):
            feedback.pushConsoleInfo('Generating tiles for zoom level: %s' % zoom)

            for i, metatile in enumerate(metatiles_by_zoom[zoom]):
                if feedback.isCanceled():
                    break

                size = QSize(tile_width * metatile.rows(), tile_height * metatile.columns())
                extent = QgsRectangle(*metatile.extent())
                settings.setExtent(wgs_to_dest.transformBoundingBox(extent))
                settings.setOutputSize(size)

                if hasattr(settings, 'setLabelBoundaryGeometry'):
                    label_area = QgsRectangle(settings.extent())
                    lab_buffer = label_area.width() * (lab_buffer_px / size.width())
                    label_area.set(
                        label_area.xMinimum() + lab_buffer,
                        label_area.yMinimum() + lab_buffer,
                        label_area.xMaximum() - lab_buffer,
                        label_area.yMaximum() - lab_buffer
                    )
                    settings.setLabelBoundaryGeometry(QgsGeometry.fromRect(label_area))

                image = QImage(size, QImage.Format_ARGB32_Premultiplied)
                image.fill(Qt.transparent)
                dpm = settings.outputDpi() / 25.4 * 1000
                image.setDotsPerMeterX(dpm)
                image.setDotsPerMeterY(dpm)
                painter = QPainter(image)
                job = QgsMapRendererCustomPainterJob(settings, painter)
                job.renderSynchronously()
                painter.end()

                # For analysing metatiles (labels, etc.)
                # metatile_dir = os.path.join(output_dir, str(zoom))
                # os.makedirs(metatile_dir, exist_ok=True)
                # image.save(os.path.join(metatile_dir, 'metatile_%s.png' % i))

                for r, c, tile in metatile.tiles:
                    tile_img = image.copy(tile_width * r, tile_height * c, tile_width, tile_height)
                    writer.write_tile(tile, tile_img)

                progress += 1
                feedback.setProgress(100 * (progress / metatiles_count))

        writer.close()

    def checkParameterValues(self, parameters, context):
        min_zoom = self.parameterAsInt(parameters, self.ZOOM_MIN, context)
        max_zoom = self.parameterAsInt(parameters, self.ZOOM_MAX, context)
        if max_zoom < min_zoom:
            return False, self.tr('Invalid zoom levels range.')

        return super().checkParameterValues(parameters, context)


########################################################################
# MBTiles
########################################################################
class MBTilesWriter:
    def __init__(self, filename):
        base_dir = os.path.dirname(filename)
        os.makedirs(base_dir, exist_ok=True)
        self.filename = filename

    def set_parameters(self, tile_params):
        self.extent = tile_params.get('extent')
        self.tile_width = tile_params.get('width', 256)
        self.tile_height = tile_params.get('height', 256)
        self.min_zoom = tile_params.get('min_zoom')
        self.max_zoom = tile_params.get('max_zoom')
        tile_format = tile_params['format']
        if tile_format == 'JPG':
            tile_format = 'JPEG'
            options = ['QUALITY=%s' % tile_params.get('quality', 75)]
        else:
            options = ['ZLEVEL=8']
        driver = gdal.GetDriverByName('MBTiles')
        ds = driver.Create(self.filename, 1, 1, 1, options=['TILE_FORMAT=%s' % tile_format] + options)
        ds = None

        self._execute_sqlite(
            "INSERT INTO metadata(name, value) VALUES ('{}', '{}');".format('minzoom', self.min_zoom),
            "INSERT INTO metadata(name, value) VALUES ('{}', '{}');".format('maxzoom', self.max_zoom),
            # will be set properly after writing all tiles
            "INSERT INTO metadata(name, value) VALUES ('{}', '');".format('bounds')
        )
        self._zoom = None

    def _execute_sqlite(self, *commands):
        conn = sqlite3.connect(self.filename)
        for cmd in commands:
            conn.execute(cmd)
        conn.commit()
        conn.close()

    def _init_zoom_layer(self, zoom):
        west_edge, south_edge, east_edge, north_edge = self.extent
        first_tile = Tile(*deg2num(north_edge, west_edge, zoom), zoom)
        last_tile = Tile(*deg2num(south_edge, east_edge, zoom), zoom)

        first_tile_extent = first_tile.extent()
        last_tile_extent = last_tile.extent()
        zoom_extent = [
            first_tile_extent[0],
            last_tile_extent[1],
            last_tile_extent[2],
            first_tile_extent[3]
        ]

        bounds = ','.join(map(str, zoom_extent))
        self._execute_sqlite("UPDATE metadata SET value='{}' WHERE name='bounds'".format(bounds))

        self._zoom_ds = gdal.OpenEx(self.filename, 1, open_options=['ZOOM_LEVEL=%s' % first_tile.z])
        self._first_tile = first_tile
        self._zoom = zoom

    def write_tile(self, tile, image):
        if tile.z != self._zoom:
            self._init_zoom_layer(tile.z)

        data = QByteArray()
        buff = QBuffer(data)
        image.save(buff, 'PNG')

        mmap_name = '/vsimem/' + uuid4().hex
        gdal.FileFromMemBuffer(mmap_name, data.data())
        gdal_dataset = gdal.Open(mmap_name)
        data = gdal_dataset.ReadRaster(0, 0, self.tile_width, self.tile_height)
        gdal_dataset = None
        gdal.Unlink(mmap_name)

        xoff = (tile.x - self._first_tile.x) * self.tile_width
        yoff = (tile.y - self._first_tile.y) * self.tile_height
        self._zoom_ds.WriteRaster(xoff, yoff, self.tile_width, self.tile_height, data)

    def close(self):
        self._zoom_ds = None
        bounds = ','.join(map(str, self.extent))
        self._execute_sqlite("UPDATE metadata SET value='{}' WHERE name='bounds'".format(bounds))


class TilesXYZAlgorithmMBTiles(TilesXYZAlgorithmBase):
    OUTPUT_FILE = 'OUTPUT_FILE'

    def initAlgorithm(self, config=None):
        super(TilesXYZAlgorithmMBTiles, self).initAlgorithm()
        self.addParameter(QgsProcessingParameterFileDestination(self.OUTPUT_FILE,
                                                                self.tr('Output file (for MBTiles)'),
                                                                self.tr('MBTiles files (*.mbtiles)'),
                                                                optional=True))

    def name(self):
        return 'tilesxyzmbtiles'

    def displayName(self):
        return self.tr('Generate XYZ tiles (MBTiles)')

    def group(self):
        return self.tr('Raster tools')

    def groupId(self):
        return 'rastertools'

    def processAlgorithm(self, parameters, context, feedback):
        output_file = self.parameterAsString(parameters, self.OUTPUT_FILE, context)
        if not output_file:
            raise QgsProcessingException(self.tr('You need to specify output filename.'))

        writer = MBTilesWriter(output_file)
        self.generate(writer, parameters, context, feedback)

        results = {'OUTPUT_FILE': output_file}
        return results


########################################################################
# Directory
########################################################################
LEAFLET_TEMPLATE = '''
<!DOCTYPE html>
<html>
<head>
  <title>{tilesetname}</title>
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0">

  <link rel="stylesheet" href="https://unpkg.com/leaflet@1.5.1/dist/leaflet.css"
   integrity="sha512-xwE/Az9zrjBIphAcBb3F6JVqxf46+CDLwfLMHloNu6KEQCAWi6HcDUbeOfBIptF7tcCzusKFjFw2yuvEpDL9wQ=="
   crossorigin=""/>
  <script src="https://unpkg.com/leaflet@1.5.1/dist/leaflet.js"
   integrity="sha512-GffPMF3RvMeYyc1LWMHtK8EbPv0iNZ8/oTtHPx9/cc2ILxQ+u905qIwdpULaqDkyBKgOaB57QTMg7ztg8Jm2Og=="
   crossorigin=""></script>
  <style type="text/css">
    #map{{
       left: 10px;
       right: 10px;
       top: 10px;
       bottom: 10px;
       width: 600px; 
       height: 400px;
    }}
  </style>
</head>
<body>
  <div id="map"></div>
  <script>
      var map = L.map('map').setView([{centery}, {centerx}], {avgzoom});
      L.tileLayer({tilesource}, {{
        minZoom: {minzoom},
        maxZoom: {maxzoom},
        tms: {tms},
        attribution: 'Generated by TilesXYZ'
      }}).addTo(map);
  </script>
</body>
</html>
'''


class DirectoryWriter:
    def __init__(self, folder, is_tms):
        self.folder = folder
        self.is_tms = is_tms

    def set_parameters(self, tile_params):
        self.format = tile_params.get('format', 'PNG')
        self.quality = tile_params.get('quality', -1)

    def write_tile(self, tile, image):
        directory = os.path.join(self.folder, str(tile.z), str(tile.x))
        os.makedirs(directory, exist_ok=True)
        ytile = tile.y
        if self.is_tms:
            ytile = tms(ytile, tile.z)
        path = os.path.join(directory, '{}.{}'.format(ytile, self.format.lower()))
        image.save(path, self.format, self.quality)
        return path

    def close(self):
        pass


class TilesXYZAlgorithmDirectory(TilesXYZAlgorithmBase):
    TMS_CONVENTION = 'TMS_CONVENTION'
    OUTPUT_DIRECTORY = 'OUTPUT_DIRECTORY'
    OUTPUT_HTML = 'OUTPUT_HTML'

    def initAlgorithm(self, config=None):
        super(TilesXYZAlgorithmDirectory, self).initAlgorithm()
        self.addParameter(QgsProcessingParameterBoolean(self.TMS_CONVENTION,
                                                        self.tr('Use inverted tile Y axis (TMS convention)'),
                                                        defaultValue=False,
                                                        optional=True))
        self.addParameter(QgsProcessingParameterFolderDestination(self.OUTPUT_DIRECTORY,
                                                                  self.tr('Output directory'),
                                                                  optional=True))
        self.addParameter(QgsProcessingParameterFileDestination(self.OUTPUT_HTML,
                                                                self.tr('Output html (Leaflet)'),
                                                                self.tr('HTML files (*.html)'),
                                                                optional=True))

    def name(self):
        return 'tilesxyzdirectory'

    def displayName(self):
        return self.tr('Generate XYZ tiles (Directory)')

    def group(self):
        return self.tr('Raster tools')

    def groupId(self):
        return 'rastertools'

    def processAlgorithm(self, parameters, context, feedback):
        is_tms = self.parameterAsBoolean(parameters, self.TMS_CONVENTION, context)
        output_html = self.parameterAsString(parameters, self.OUTPUT_HTML, context)
        output_dir = self.parameterAsString(parameters, self.OUTPUT_DIRECTORY, context)
        if not output_dir:
            raise QgsProcessingException(self.tr('You need to specify output directory.'))

        writer = DirectoryWriter(output_dir, is_tms)
        self.generate(writer, parameters, context, feedback)

        results = {'OUTPUT_DIRECTORY': output_dir}

        if output_html:
            output_dir_safe = output_dir.replace('\\', '/')
            html_code = LEAFLET_TEMPLATE.format(
                tilesetname="Leaflet Preview",
                centerx=self.wgs_extent[0] + (self.wgs_extent[2] - self.wgs_extent[0]) / 2,
                centery=self.wgs_extent[1] + (self.wgs_extent[3] - self.wgs_extent[1]) / 2,
                avgzoom=(self.max_zoom + self.min_zoom) / 2,
                tilesource="'file:///{}/{{z}}/{{x}}/{{y}}.{}'".format(output_dir_safe, self.tile_format.lower()),
                minzoom=self.min_zoom,
                maxzoom=self.max_zoom,
                tms='true' if is_tms else 'false'
            )
            with open(output_html, "w") as fh:
                fh.write(html_code)
            results['OUTPUT_HTML'] = output_html

        return results